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Adaptation of liquid reactive process for composite thermoplastic manufacturing has been studied through the polyamide 6 case. Its polymerisation from the ε-caprolactam monomer involves simultaneously the crystallisation of the growing chains over the temperature range. In order to understand and predict the coupling between both phenomena, an experimental study of PA6 synthesis has been achieved in isothermal conditions by means of DSC technique. Different shapes of curves have been obtained, depending of the level of coupling between polymerisation and crystallisation. The final degree of conversion, characterised by TGA, has been recorded between 92 and 97 wt.%, indicating a high reaction yield. The crystalline phase obtained has been characterised by DSC and WAXS. The samples showed a high crystallinity of α-type form. This database has been used as input for the development of a kinetic model of PA6 synthesis. Polymerisation was described by Malkin’s model and crystallisation by Nakamura’s model. The Hillier’s coupling has been adapted to the polymerisation/crystallisation case by adding a correction factor, allowing a better prediction of each mechanism. Thanks to this model, the isothermal TTT diagrams of the PA6 synthesis has been established.
liquid reactive process, thermoplastic composite, synthesis kinetics, coupling modelling, DSC
Les auteurs tiennent à remercier Brüggemann Chemical, Germany pour avoir gracieusement fourni les produits de cette réaction.
Aharoni S. M. (1997). n-Nylons: Their Synthesis, Structure, and Properties. John Wiley & Sons, Inc.
Bolgov S. A., Begishev V. P., Malkin A. Y. & Frolov V. G. (1981). Role of the functionality of activators during isothermal crystallization accompanying the activated anionic polymerization of ε-caprolactam. Polymer Science U.S.S.R., vol. 23, n°6, p. 1485–1492.
Bukac Z., Cefelin P., Doskocilová D. & Šebenda J. (1964). Alkaline polymerization of 6-caprolactam. XVIII. Equilibrium between monomer and polymer. Collect. Czech. Chem. Commun., vol. 29, n°11, p. 2615-2625.
Camargo R. E., Gonzalez V. M., Macosko C. W. & Tirrell M. (1983). Bulk polymerization kinetics by the adiabatic reactor method. Rubber Chemistry and Technology, vol. 56, n°4, p. 774–783.
Davé R. S., Udipi K., Kruse R. L. & Stebbins L. R. (1997). Polyamides from lactams via anionic ring-opening polymerization: 2. Kinetics. Polymer, vol. 38, n°4, p. 939–947.
Davé R. S., Kruse R. L., Udipi K. & Williams D. E. (1997). Polyamides from lactams via anionic ring-opening polymerization: 3. Rheology. Polymer, vol. 38, n°4, p. 949-954.
Duplay C., Monasse B., Haudin J.-M. & Costa J.-L. (2000). Shear-induced crystallization of polypropylene: Influence of molecular weight. Journal of Materials Science, vol. 35, n°24, p. 6093–6103.
Fatou J. G., Marco C. & Mandelkern L. (1990). The crystallization kinetics of low-molecularweight polyethylene fractions. Polymer, vol. 31, n°5, p.890–898.
Fournier J., Williams G., Duch C. & Aldridge G. (1996). Changes in molecular dynamics during bulk polymerization of an epoxide-amine system as studied by dielectric relaxation spectroscopy. Macromolecules, vol. 29, n°22, p. 7097–7107.
Gahleitner M., Bernreitner K., Neissl W., Paulik C. & Ratajski E. (1995). Influence of molecular structure on crystallization behaviour and mechanical properties of polypropylene. Polymer Testing, vol. 14, n°2, p. 173–187.
Hillier I. H. (1965). Modified Avrami equation for the bulk crystallization kinetics of spherulitic polymers. Journal of Polymer Science Part A: General Papers, vol. 3, n°9, p. 3067–3078.
Hoffman J. D. (1964). Theoretical aspects of polymer crystallization with chain folds: Bulk polymers. Polymer Engineering & Science, vol. 4, n°4, p. 315–362.
Hoffman J. D. (1976). Treatise on Solid State Chemistry. Springer. Illers K.-H. & Haberkorn H. (1971). Schmelzverhalten, Struktur und Kristallinität von 6-Polyamid. Die Makromolekulare Chemie, vol. 142, p. 31–67.
Illers K.-H. (1978). Polymorphie, Kristallinität und Schmelzwärme von Poly(ε-caprolactam). Die Makromolekulare Chemie, vol. 179, p. 497–507.
Khodabakhshi K. (2011). Anionic Polymerisation of caprolactam: an approach to optimising the polymerisation conditions to be used in a jetting process, Thèse, Loughborough University.
Kim K. J., Kim Y. Y., Yoon B. S. & Yoon K. J. (1995). Mechanism and kinetics of adiabatic anionic polymerization of ε-caprolactam in the presence of various activators. Journal of Applied Polymer Science, vol. 57, n°11, p. 1347–1358.
Kolesov I., Mileva D., Androsch R. & Schick C. (2011). Structure formation of polyamide 6 from the glassy state by fast scanning chip calorimetry. Polymer, vol. 52, n°22, p. 5156–5165.
Lee K. H. & Kim S. C. (1988). Reaction-induced crystallization kinetics during the anionic polymerization of ε-caprolactam. Polymer Engineering & Science, vol. 28, n°1, p. 13–19.
Lin D. J., Ottino J. M. & Thomas E. L. (1985). A kinetic study of the activated anionic polymerization of ε-caprolactam. Polymer Engineering & Science, vol. 25, n°18, p. 1155–1163.
Lindenmeyer P. H. (1969). Imperfections in polymer crystals. Kolloid-Zeitschrift und Zeitschrift für Polymere, vol. 231, n°1, p. 593–605.
Magill J. H. (1962). Crystallization kinetics study of nylon 6. Polymer, vol. 3, p. 655–664.
Magill J. H. (1964). Crystallization of poly-(tetramethyl-p-silphenylene)-siloxane polymers. Journal of Applied Physics, vol. 35, n°11, p. 3249–3259.
Malkin A. Y., Beghishev V. P., Keapin I. A. & Andrianova Z. S. (1984). General treatment of polymer crystallization kinetics - Part 2. The kinetics of nonisothermal crystallization. Polymer Engineering & Science, vol. 24, n°18, p. 1402–1408.
Nakamura K., Watanabe T., Katayama K. & Amano T. (1972). Some aspects of nonisothermal crystallization of polymers. I. Relationship between crystallization temperature, crystallinity, and cooling conditions. Journal of Applied Polymer Science, vol. 16, n°5, p. 1077–1091.
Nakamura K., Katayama K. & Amano T. (1973). Some aspects of nonisothermal crystallization of polymers. II. Consideration of the isokinetic condition. Journal of Applied Polymer Science, vol. 17, n°4, p. 1031–1041.
Okui N., Umemoto S., Kawano R. & Mamun A. (2007). Temperature and Molecular Weight Dependencies of Polymer Crystallization. Springer Berlin Heidelberg, p. 391–425.
Orange G., Bessard E., Bréard J., Bizet L., Bailleul J.-L., Binetruy C., Boisse P. & Gomina M. (2014). Development of composite parts with RTM process based on new high fluidity thermoplastic polymers. Proceedings of FPCM-12.
Reimschuessel H. K. (1969). Kinetics of Hydrolytic Polymerization. Ring-Opening Polymerization. Marcel Dekker, p. 303–326.
Russo S., Maniscalco S., Moretti P. & Ricco L. (2013). Fast-activated anionic polymerization of ε-caprolactam in the bulk under quasi-adiabatic conditions: Comparison of different kinetic models. Journal of Polymer Science Part A: Polymer Chemistry, vol. 51, n°20, p. 4474–4480.
Schick C. & Mathot V. (2016). Fast Scanning Calorimetry. Springer International Publishing.
Teuwen J. J. E. (2011). Thermoplastic composite wind turbine blades - Kinetics and processability. Thèse, Technische Universiteit Delft.
Umemoto S. & Okui N. (2005). Power law and scaling for molecular weight dependence of crystal growth rate in polymeric materials. Polymer, vol. 46, n°20, p. 8790–8795.
Van Antwerpen F. & Van Krevelen D. W. (1972). Influence of crystallization temperature, molecular weight, and additives on the crystallization kinetics of poly(ethylene terephthalate). Journal of Polymer Science: Polymer Physics Edition, vol. 10, n°12, p. 2423–2435.
Van Rijswijk K. (2007). Thermoplastic composite wind turbine blades - Vacuum infusion technology for anionic polyamide-6 composites. Thèse, Technische Universiteit Delft.
Wichterle O., Sebenda J. & Kralicek J. (1961). The anionic polymerization of caprolactam. Advances in Polymer Science, vol. 2, n°4, p.578–595.
Wichterle O., Tomka J. & Sebenda J. (1964). Alkalische Polymerisation des 6-Caprolactams XII. Über die Polymerisation von 6-Caprolactam und die Kristallisation des gebildeten Polymeren unter adiabatischen Bedingungen. Collect. Czech. Chem. Commun., vol. 29, n°3, p. 610–624.
Wilfong D. L., Pommerening C. A. & Gardlund Z. G. (1992). Separation of polymerization and crystallization processes for nylon-6. Polymer, vol. 33, n°18, p. 3884–3888.